This invention relates to a laminate cutting apparatus for automatically cutting a laminate consisting of multiple plies of a sheet material such as a fabric.
Heretofore, an automatic laminate cutting apparatus of the type mentioned above is disclosed in, for example, Japanese Patent Publication No. Sho 53-13836. In this conventional apparatus, a laminate such as a fabric to be cut is supported on a supporting surface of an air-permeable support member, and by withdrawing air from the under surface of the support member, the laminate is supported on the supporting surface in a compressed state. In that state, a knife-like cutter as a cutting tool is penetrated into the laminate from above, so that the laminate is cut into a desired shape.
The inventor of the present invention has also proposed a laminate cutting apparatus as discussed in Japanese Patent Application Laid-Open (KOKAI) No. Hei 1-306200. This conventional cutting apparatus includes a pedestal, a belt support mechanism provided with a number of belt support plates arranged in parallel in the longitudinal direction (forward and backward direction) so as to be raised and lowered, a laminate supporting belt supported on the pedestal through the belt support mechanism and capable of reciprocating longitudinally, and a travel body supported on the pedestal and capable of reciprocating longitudinally. The travel body is provided with a recess forming member for forming a movable recess having an open upper surface in a longitudinal part of the support belt, a cutter head capable of reciprocating transversely above the support belt, and a cutter receiving sleeve capable of reciprocating transversely within the movable recess in synchronism with this cutter head. A knife-like cutter is mounted on the cutter head with its tip portion inserted into the cutter receiving sleeve such that the cutter is capable of moving up and down. The pedestal is provided on both sides thereof with suction ducts having suction ports opening up at their opposing surfaces.
With this cutting apparatus, an air-permeable laminate such as a fabric, which is covered at all surfaces excepting side surfaces thereof with an air-impermeable sheet, is supported on the supporting belt, and air is withdrawn from both side surfaces of the laminate through the suction duct, so that the laminate is held in a compressed state on the supporting belt.
In that state, the cutter is lowered to insert its tip portion into the cutter receiving sleeve, the cutter head is reciprocated transversely, and the travel body is reciprocated longitudinally, whereby the laminate is cut into a desired shape.
Furthermore, as shown in Japanese Patent Application Laid-Open (KOKAI) No. Hei 1-199789, there is also known a laminate cutting apparatus, in which a movable recess is formed in a laminate supporting belt by a recess forming member secured to a moving pedestal on which a high speed jet cutter apparatus is mounted, a number of vent holes are formed in the supporting belt, a front and a rear suction boxes are secured to the moving pedestal and adapted to support the under surface of the supporting belt at a front and a rear locations of the movable recess, suction chambers each having an open upper surface are formed within the front and rear suction boxes, and the suction chambers are connected to the suction source.
In this cutting apparatus, the laminate is supported on the supporting belt in the compressed state by sucking air from the suction source via the suction chambers, suction ports and vent holes, and cut by hydraulic pressure of a high pressure jet stream from the jet cutter apparatus.
Since the laminate cutting apparatus shown in the aforementioned Publication No. Sho 53-13836 is a cantilever type cutter in which the laminate retained in a compressed state on the supporting surface by suction is penetrated by the knife-like cutter and the tip portion of the cutter is also penetrated in the area near the supporting surface of the support member, the tip portion of the cutter is twisted by resistance of the laminate and support member. The result is that a cut product of high accuracy is difficult to obtain. A band saw type cutter is sometimes used as a cutting tool. In this case, however, when the laminate is cut by the cutter, the laminate and the support member are simultaneously cut by the cutter. Since it is necessary to change the support member highly frequently, the working ratio is bad.
On the other hand, in the laminate cutting apparatus disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 1-199798, since the front and rear suction boxes are disposed at only the portion near the movable recess of the supporting belt and the laminate being supported on the supporting belt in the compressed state occurs at only the portion near the movable recess (in other words, the whole laminate is not sucked in the effective area for cutting the laminate), the laminate can be cut with high accuracy.
Particularly, in the case where the laminate is a fabric of a material having a raised nap such as velvet, moquette, or corduroy, when compressing and decompressing operations are performed repeatedly on the laminate, the laminate is gradually de-shaped in the direction where hairs of the fabric are fallen and a significant positional displacement is occurred between the upper layer fabric and the lower layer fabric, with the results that cutting accuracy is lowered and in addition, cutting becomes impossible to carry out.
With respect to the above-mentioned Publication No. Hei 1-306200, in the case where the sheet materials forming the laminate are not sufficient in air-permeating property, even if air is sucked with the suction ports of the suction ducts are abutted against both sides surfaces of the sheet materials, the intimately attaching force between the laminated sheet materials is weak at location away from the suction ports and the laminated state is collapsed due to cutting resistance of the cutter, with the result that a cut product of high accuracy is impossible to obtain. Furthermore, in the case of the one where the suction ports of the suction ducts are abutted against both side surfaces of the laminate, it is necessary to move the suction ducts in the transverse direction every time the width of the laminate is changed and therefore, it takes much time and labor and the working ratio is lowered.